Anonymous user
File input/output: Difference between revisions
→{{header|C}}: mmap
(→{{header|C}}: buf size, file mode, etc.) |
(→{{header|C}}: mmap) |
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Line 257:
copy_file("infile", "outfile");
return 0;
}</lang>
If it's certain that mapping the whole input file into memory poses no problem (there can be all kinds of problems), this may be the most efficient:<lang c>int copy_file(char *in, char *out)
{
int ret = 0;
int fin, fout;
char *bi;
struct stat st;
if ((fin = open(in, O_RDONLY)) == -1) return 0;
if (fstat(fin, &st)) goto bail;
fout = open(out, O_WRONLY|O_CREAT|O_TRUNC, st.st_mode & 0777);
if (fout == -1) goto bail;
bi = mmap(0, st.st_size, PROT_READ, MAP_PRIVATE, fin, 0);
ret = (bi == (void*)-1)
? 0 : (write(fout, bi, st.st_size) == st.st_size);
bail: if (fin != -1) close(fin);
if (fout != -1) close(fout);
if (bi != (void*)-1) munmap(bi, st.st_size);
return ret;
}</lang>
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